The present invention relates to an apparatus and method that enables a user to download digital data from a digital broadcast signal and to combine the data with an analog composite television signal for display.
The ATSC digital broadcast standard for digital television allows for the transmission of 19 Mbits/sec in an RF channel having a 6 MHZ bandwidth. Although this allocated bandwidth is adequate for a single analog NTSC television channel, the ATSC bit rate permits the same channel to support the concurrent transmission of several standard definition television (SDTV) programs (i.e., programs displayable with a resolution comparable to that of the NTSC analog program). Alternatively, the allocated bandwidth at the ATSC bit rate permits a channel to support the transmission of a single high definition television (HDTV) program at a time. Moreover, the ATSC digital broadcast standard permits data to be transmitted in the channel along with digital programming. Therefore, data packets may be multiplexed in the channel with video and audio program packets.
In contrast, the NTSC analog broadcast standard for analog television allocates bandwidth within the vertical blanking interval for the transmission of data with an analog television broadcast program. However, the bandwidth allocated within the vertical blanking interval of an NTSC signal is minimal compared to the amount of bandwidth available in an ATSC digital broadcast signal for the transmission of digital data.
In light of the greater bandwidth available in an ATSC broadcast signal, an ATSC signal can support the transmission of greater amounts of data than can the NTSC signal. However, conventional analog televisions, that are capable of receiving and displaying an analog NTSC signal, are incapable of receiving a digital broadcast signal. Therefore, the consumer having an analog NTSC television is not able to receive the data being transmitted in the digital broadcast signal. Moreover, even if such data could be received from a digital broadcast signal by an analog television, conventional analog televisions are not equipped to combine digital data with an analog composite television signal for display to the television consumer.
The present invention is directed to a method and apparatus that enables the reception of digital data transmitted in a digital broadcast signal and the combination of such data with an analog composite television signal for display.
In accordance with one aspect of the present invention, a television system includes an analog tuner that tunes to an analog programming signal and an analog signal demodulator coupled to the analog tuner that demodulates the analog programming signal. The system further includes a digital tuner that tunes to a digital programming signal and a digital signal demodulator coupled to the digital tuner that demodulates the digital programming signal. In addition, a display is coupled to the analog and digital signal demodulators and displays analog programming contained in the demodulated analog programming signal, and further displays data as contained in one or more digital data packets transmitted in the digital broadcast signal.
In accordance with another aspect of the present invention, the analog broadcast signal has both an analog programming signal component and an analog information signal component that includes information pertaining to a digital channel from which the one or more digital packets may be extracted. The analog information signal component further includes information pertaining to an identifier for identifying the one or more digital data packets to be extracted from the digital broadcast signal.
In accordance with yet another aspect of the present invention, a television system is provided wherein both an analog program signal and an digital program signal are received and wherein an analog program is extracted from the analog program signal and is displayed on a display, and further wherein data are extracted from the digital program signal and are displayed on the display.
In accordance with a still further embodiment of the present invention, a method for receiving a digital broadcast signal and for combining the digital broadcast signal with an analog broadcast signal includes the steps of: a) tuning to and receiving the analog broadcast signal; b) demodulating the analog broadcast signal; c) tuning to and receiving the digital broadcast signal; d) demodulating the digital broadcast signal; e) separating a digital data packet from the digital broadcast signal; f) formatting data contained in the digital data packet for display, thereby generating a formatted data signal; g) combining the formatted data signal with the demodulated analog broadcast signal thereby to form a combined signal; and h) supplying the combined signal to a display for display thereon.
The method may further includes the steps of i) separating an analog information signal from the analog broadcast signal; j) using information contained in the analog information signal to select a channel to which the digital tuner is to be tuned in step c); and k) using information contained in the information signal to identify the data packet to be separated from the digital broadcast signal in step e). The steps i) and j) are to be performed between the steps c) and d) and the step k) is to be performed between the steps d) and e).